/******************************************************************************
 * Spine Runtimes License Agreement
 * Last updated January 1, 2020. Replaces all prior versions.
 *
 * Copyright (c) 2013-2020, Esoteric Software LLC
 *
 * Integration of the Spine Runtimes into software or otherwise creating
 * derivative works of the Spine Runtimes is permitted under the terms and
 * conditions of Section 2 of the Spine Editor License Agreement:
 * http://esotericsoftware.com/spine-editor-license
 *
 * Otherwise, it is permitted to integrate the Spine Runtimes into software
 * or otherwise create derivative works of the Spine Runtimes (collectively,
 * "Products"), provided that each user of the Products must obtain their own
 * Spine Editor license and redistribution of the Products in any form must
 * include this license and copyright notice.
 *
 * THE SPINE RUNTIMES ARE PROVIDED BY ESOTERIC SOFTWARE LLC "AS IS" AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL ESOTERIC SOFTWARE LLC BE LIABLE FOR ANY
 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES,
 * BUSINESS INTERRUPTION, OR LOSS OF USE, DATA, OR PROFITS) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THE SPINE RUNTIMES, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *****************************************************************************/

using UnityEngine;
using System.Collections;
using System;

namespace Spine.Unity {
    /// <summary>
    /// Use this as a condition-blocking yield instruction for Unity Coroutines.
    /// The routine will pause until the AnimationState.TrackEntry fires any of the
    /// configured events.
    /// <p/>
    /// See the <see cref="http://esotericsoftware.com/spine-unity-events">Spine Unity Events documentation page</see>
    /// and <see cref="http://esotericsoftware.com/spine-api-reference#AnimationStateListener"/>
    /// for more information on when track events will be triggered.</summary>
    public class WaitForSpineAnimation : IEnumerator {
        [Flags]
        public enum AnimationEventTypes { Start = 1, Interrupt = 2, End = 4, Dispose = 8, Complete = 16 }

        bool m_WasFired = false;

        public WaitForSpineAnimation(Spine.TrackEntry trackEntry, AnimationEventTypes eventsToWaitFor) {
            SafeSubscribe(trackEntry, eventsToWaitFor);
        }

        #region Reuse
        /// <summary>
        /// One optimization high-frequency YieldInstruction returns is to cache instances to minimize GC pressure.
        /// Use NowWaitFor to reuse the same instance of WaitForSpineAnimationComplete.</summary>
        public WaitForSpineAnimation NowWaitFor(Spine.TrackEntry trackEntry, AnimationEventTypes eventsToWaitFor) {
            SafeSubscribe(trackEntry, eventsToWaitFor);
            return this;
        }
        #endregion

        #region IEnumerator
        bool IEnumerator.MoveNext() {
            if (m_WasFired) {
                ((IEnumerator)this).Reset(); // auto-reset for YieldInstruction reuse
                return false;
            }

            return true;
        }

        void IEnumerator.Reset() {
            m_WasFired = false;
        }

        object IEnumerator.Current { get { return null; } }
        #endregion

        protected void SafeSubscribe(Spine.TrackEntry trackEntry, AnimationEventTypes eventsToWaitFor) {
            if (trackEntry == null) {
                // Break immediately if trackEntry is null.
                Debug.LogWarning("TrackEntry was null. Coroutine will continue immediately.");
                m_WasFired = true;
            } else {
                if ((eventsToWaitFor & AnimationEventTypes.Start) != 0)
                    trackEntry.Start += HandleComplete;
                if ((eventsToWaitFor & AnimationEventTypes.Interrupt) != 0)
                    trackEntry.Interrupt += HandleComplete;
                if ((eventsToWaitFor & AnimationEventTypes.End) != 0)
                    trackEntry.End += HandleComplete;
                if ((eventsToWaitFor & AnimationEventTypes.Dispose) != 0)
                    trackEntry.Dispose += HandleComplete;
                if ((eventsToWaitFor & AnimationEventTypes.Complete) != 0)
                    trackEntry.Complete += HandleComplete;
            }
        }

        void HandleComplete(TrackEntry trackEntry) {
            m_WasFired = true;
        }
    }
}
